Signal was a modern, glossy, illustrated photo journal and army propaganda tool, meant specifically for audiences in neutral, allied, and occupied countries. A German edition was distributed in Switzerland and to various countries with a strong German military presence, but Signal was never distributed in Germany proper. The promoter of the magazine was the chief of the Wehrmacht propaganda office, Colonel Hasso von Wedel. Signal was published fortnightly (plus some special issues) in as many as 25 editions and 30 languages, and at its height had a circulation of 2,500,000 copies. It was available in the United States in English until December 1941. The last number was 6/45, only known in one sample from the Swedish edition.

Signal described the combat conditions of the German troops and their allies in all fronts, together with high quality photos, including a central double page full color one. Many of the most famous photos of World War II to be seen today are taken from Signal. The magazine also included articles about economics, science, arts, and advertising for the most well-known German companies (e.g., BMW, Agfa, Audi, Siemens, etc.). The contents of the different editions could vary, sometimes avoiding subjects that could upset or worry the population of that country (for example, the discovery of the Katyn massacre of Polish officers taken prisoners by the Soviets in 1940 was not covered by all editions).